"There are no people left to recover from under the rubble in any village, and all necessary aid is currently being distributed," an interior ministry official in charge of disaster management, Hossein Ghadami, told state television.
He said he hoped the death toll would not rise further. Some of those critically injured had already succumbed to their wounds.
The earthquakes struck on Saturday afternoon within 11 minutes of each other.
The first registered a strong 6.4 on the moment magnitude scale while the second, a strong aftershock, registered 6.3, according to the US Geological Survey, which monitors seismic activity worldwide.
While the biggest city in the region, Tabriz, and nearby towns escaped with only relatively minor damage, outlying villages made of mud and concrete bricks were flattened.
AFP journalists in the zone saw exhausted residents mourning their loved ones.
Grieving women wailed over the bodies of the dead, many of whom were women and children. Residents said many of the villages' men had been working their fields when the disaster struck.
"I was working on my farm, on my tractor, and I felt the earth shake and I was thrown off the vehicle," a 40-year-old farmer in one hamlet, Qanbar Mehdizade, told AFP.
His family, who had been working with him, survived, but in many villages it was a different story.
"This village is a mass grave," said Alireza Haidaree, an emergency worker who supervised a bulldozer working in the village of Baje Baj, where 33 of the 414 inhabitants died.
"There are so many other villages that have been completely destroyed," he added.
Rescue personnel who had worked through the night to free trapped survivors switched to assisting the estimated 16,000 homeless, providing tents, blankets, food, water and medical help.
A Red Crescent spokesman, Hossein Derakhshan, was quoted by the Fars news agency as saying nearly 6,000 tents had been distributed, along with 18,000 cans of food.
Emergency workers were sent from 14 provinces around Iran to help, drawing on services and resources built up through the country's long experience in dealing with seismic instability.
Iran sits astride several major fault lines and is prone to frequent earthquakes, some of which have been devastating.
The deadliest was a 6.6-magnitude quake which struck the southeastern city of Bam in December 2003, killing 31,000 people -- about a quarter of the population -- and destroying the city's ancient mud-built citadel.
While this latest disaster was not on the same scale, it did stretch Iran's ability to respond.
"The magnitude of the disaster is so huge that officials are just managing to get enough people in from other provinces to help out," one Red Crescent worker said, as he handed out bread and emergency supplies.
Ghadami, the interior ministry official, said 110 of the region's 500 villages were damaged. Some half a dozen closest to the quakes' epicentres were entirely wiped off the map.
Even into Sunday, the earth trembled from time to time from one of more than 50 aftershocks, jarring the nerves of those who had spent a terrified, chilly night sleeping in the open.
President Mahmoud Ahmadinejad's office posted a statement on its website expressing condolences to those in the disaster zone and calling on authorities to "mobilise all efforts to help the affected populations."